Improvement in log-sawing machine



well-known means anna am@ fair/nt (utilita f C. BOARDMAN, OF MORRISVILLE, VERMONT. f

Lenen Patent No. 90,071, and May 1s, 1869.

.mPRovEMEN'r IN Loa-SAWING MACHINE.

` 'The Schedule referred to .in these Letters Patent and making part of thesame.

i tion thereof', `reference being had to the accompanying drawings, making part of this specification, in which- 'Figure 1, sheet 1, is longitudinal section; taken `in a vertical plane through the centre of the log-carriage and its bed, indicating the saw and a log inred Figure 2, sheet 1, is a plan view,indicating the carriage in the act of feeding a log `up to its work. v l Figure 3, sheet. 1, is a similar view of the same parts V:shown in Iig. 2', indicating the log-carriage. in theact of receding `after the operation of` sawing aslab from la log.` i

i t Figure 4, sheet 2,Y is an end elevation of the parts shown iniig. 2, showing them in the same position as l in the figure.`

` Figure 5, sheet 2, is a similar view, representing the parts in the position as indicated in iig. 3. n

` Similar letters of reference indicate corresponding?,

parts in the several figures.

' i The object of this` invention and improvement in saw-mills for sawing logs into slabs or boards, is to prevent wear and injury to the teeth of a saw `by its contact `with a log, during the act of gigging back the log,

`preparatory to commencing another cut.

It is well known among practical sawyers that the set of the teeth of a circularysaw, as well as their cntting-edges, is very rapidly impaired,\in consequence of allowing the face of a log to run closeto the saw,

`While gigging back the log.

To obviate this objection, the nature of .my inven-l tion |consists in allowing `the log-carriage to have a `bodily lateral play upon its rollers, or guide-wheels;

also, in providing beneath said carriage a friction-roller,

` which has its axis arranged obliquely to thel length of the carriage, and which is caused `to press upward against a longitudinal central rail of said carriage by agweight, or its equivalent, and to operate in such manner, that while gigging back the carriage, the face of the log, from which a board was last sawed', will be moved free from the saw, as will be hereinafter' explained. To enable others skilled in the art Fto understand `rny' invention, I will describe its construction and operation. l

In the accompanying drawings- A` represents a horizontal reciprocating log-carriage,

' which is mounted `upon rollers, or wheels a a, that have their bearings in standards b b,' np`on a suitable foundation,-G. 4

The'carriage MA should be provided wfth any of the for moving it forward and backward, and it should 'also be furnished with transverselyadj nstable head-blocks, constructed, applied, and operated in any suitable or well-known manner. On the bottom side of each longitudinal beam of the log-carriage A, are two parallel rails, or flange-guides, it, having a space between them somewhat greater than the-thickness of the perimeters of wheels, or supporting-rollers@ a, as clearly shown in figs. 4 and 5, sheet 2.

As thel grooves, or spaces, between each pair of guides, ifi, are wider than the rollers'a a, which turn therein, it is obvious that the carriage A can be moved bodily, in a lateral direction, a distance lequal to the difference between the width of the said rollers and the spaces between the guidesz i. ,Y v

This lateral movement need not be more than 4the fraction of an inch, or just suicientfto allow the face ,of a log from which a boardV hasbeensawed to clear the. saw while being gigged back. A

Along the longitudinal centre of the carriage A, and secured rigidly to the bottom thereof, is a beam, or narrow bar, B, having .a flat or plain-bottom surface, which is parallel to the horizontal surface of the carriage` be made of wood, or other substance that will afford'` `considerable friction, while pressing upwardly.- against the bar B. s k

The axis of this roller D is oblique to the length of the carriage, and so arrangedthat in' the actoi' moving the carriage backward, as indicated kby thecourse of. the arrow in fig. 3, it will move the carriage laterally away from the; saw, so that the teethfof the saw willnot strike the log, orbe worn therebyI After the carriage hasbeenmoved b Y k the length ofthe log, when it is started forward again, and just before the saw begins to cut, the oblique frictionroller D- will move the carriage and log laterally up to the work.

For the purpose of supporting the self-adjusting roller D, I prefer to.. employ a vibrating lever, G, .which has its fulcrum on standards c c, and which carries on its longest arm a weight, O', suitable for giving the required pressure of roller D against the bar Byof the log-carriage, as shown in iig. 1. 1f, at any time, it is found desirable to give more or less Obliquity to theself-adjusting roller D, this may be done by applying the latter to the forked end of a laterallyadjustable arm, E, on the shortest arm of Under certain circumstances, such as sawing very Beneath this bar B, and arranged near the saw, as shown in figs. 1, 2, and 3, is a roller, D, which may v hard wood, it may be desirable to relieve the carriage from the lateral pressure of the roller D, which .can be readily done by raising the longest arm of lever O.

To do this, I have applied a transverse lever, g, to a standard, d,'and arrange this lever, so that by pressing down upon its long arm, roller'D will be depressed free from har B.

While I prefer to support and arrange the self-adjusting roller D, as I have herein described, I do not confine myself to this precise manner of arranging and supporting it.

I do not wish to be understood as setting forth, in anyv part of my foregoing specication, that I am the first one who has provided for a lateral movement of the log-can'iage away from the saw, during the oper- 'ation of gigging back said carriage, as this is done in patents granted to William M. Ferry, November 29, 1859, and to J. Orm, September 1868.

HERVEY C. BOARDMAN.

Witnesses:

HnzEKIAH BARNES, A. M. BURKE. 

